1. Field of the Invention
The present invention relates to an image acquisition and display method and an image capturing and display apparatus for obtaining an ordinary image and a special image by projecting illumination light and special light onto an observation area and displaying the obtained ordinary and special images. More particularly, the invention relates to an auxiliary function to assist resection of a portion of the observation area in surgery or the like.
2. Description of the Related Art
Endoscope systems for observing tissues of body cavities are widely known, and electronic endoscope systems for capturing an ordinary image of an observation area in a body cavity by projecting white light onto the observation area and displaying the captured ordinary image on a monitor screen are widely used.
Further, as one of such endoscope systems, a system in which ICG (indocyanine green) is administered to an observation area in advance in order to observe, for example, a blood vessel run, blood flow, lymphatic vessel, lymph flow, bile duct run, or bile flow under fat which does not appear in an ordinary image and an ICG florescence image is captured by projecting near infrared excitation light to the observation area is proposed.
The use of such endoscope systems that capture a fluorescence image allows a lesion site, such as a tumor, in the observation area to be identified, and there may be a case that the identified tumor portion or an organ section which includes the tumor portion is desired to be resected.
When resecting a tumor or the like, it is necessary to remove the tumor area or an organ section with an added surgical margin so that no cancer cell exits in the remaining portion of the organ after surgery.
The extent of resection, including the surgical margin described above, may not be recognized, however, by simply identifying the tumor or the like in a fluorescence image.
Further, when resecting a tumor or the like, the resection is performed by observing an ordinary image of white light to begin with. Thus, even if the extent of a tumor is identified in a fluorescence image, the extent of resection, including the surgical margin, may not be recognized in the ordinary image and an appropriate resection procedure may not be performed.
Although, it is proposed, in Japanese Unexamined Patent Publication No. 2010-082041, that a surgical margin is displayed in an image obtained by an endoscope, this surgical margin is a margin simply set in advance and not a surgical margin determined based on a tumor identified in a fluorescence image captured in real time as described above.
Further, U.S. Pat. No. 6,468,204 describes that a boundary of a tumor is identified and visualized in real time using a fluorescence image captured during a surgical operation, but the surgical margin described above is not taken into consideration at all.
The present invention has been developed in view of the circumstances described above, and it is an object of the invention to provide an image acquisition and display method and an image capturing and display apparatus capable of displaying an ordinary image that allows a tumor or the like to be removed to an appropriate extent, including a surgical margin, in an endoscope system for capturing a fluorescence image like that described above.